struct nbd_reply not packed => trouble?

[Yann Droneaud]

Hi,

Le mardi 15 janvier 2013 à 07:59 +0800, 卜弋天 a écrit :
> 
> 在 2013-1-11，0:42，"Yann Droneaud" <ydroneaud at opteya.com> 写道：

> >>  - Any ideas for a platform where you would expect struct nbd_reply to
> >>    be other than 4 + 4 + 8 = 16 bytes in size?
> > 
> > Look for an ABI that require 'char' with either property:
> > - size > 1 byte
> > - alignment > 8 (16 bytes !)
> > 
> > 
> 
>       Do you mean this structure size will vary on different platform? If yes, why Linux does not packed here? Thanks
> 

There's probably no such architecture for a general purpose processor
with the ABI properties I've mentionned. eg. (sizeof(char) > 1 ||
alignof(char) > 8).

And if one day Linux is going to be ported on such target, the packing
of the nbd_reply struct will be the smallest problem to fix.

Regards

-- 
Yann Droneaud
OPTEYA